import pygame
class Ship():
	def __init__(self,screen,my_settings):
		#初始化飞船并设置其位置
		self.screen = screen
		self.my_settings = my_settings
		#加载飞船图像并获取其外接矩形
		self.image = pygame.image.load('ship.bmp')
		self.rect = self.image.get_rect()
		self.screen_rect = screen.get_rect()
		
		#将每艘飞船放置屏幕底部中央
		self.rect.centerx = self.screen_rect.centerx
		self.rect.bottom = self.screen_rect.bottom
		#在飞船的属性center中存储小数值
		self.center =float(self.rect.centerx)
		#移动标志
		self.moving_right = False
		self.moving_left = False
	def update(self):
		#根据设置的速度来调整飞船位置
		if self.moving_right and self.rect.right < self.screen_rect.right:
			self.center += self.my_settings.ship_speed_factor
		if self.moving_left and self.rect.left > 0:
			self.center -= self.my_settings.ship_speed_factor
		#根据center更新rect对象
		self.rect.centerx = self.center
	def blitme(self):
		#在指定位置绘制飞船
		self.screen.blit(self.image,self.rect)
	
